Polysaccharide-Rich Fraction of Noni Fruit (Morinda citrifolia L.) as Doxorubicin Co-Chemotherapy: Evaluation of Catalase, Macrophages, and TCD8+ Lymphocytes

Noni fruit (Morinda citrifolia L.) has been acknowledged for its cytotoxic and immunostimulatory activity. Our previous results on the immunomodulatory effect of a noni juice polysaccharide-rich fraction encouraged this research to evaluate the potency of the polysaccharide-rich fraction as co-chemotherapy with doxorubicin (DOX) administration. Macrophage activity (MA) was evaluated with the latex bead method. The phagocytic index (PI) was measured as the number of latex beads ingested by 100 macrophages, while the phagocytosis ratio (PR) was indicated by the percentage of macrophages that ingested three or more latex beads. The CEC was evaluated by using a commercial assay kit, while CD8+ T lymphocyte proliferation was evaluated using a flowcytometry method following in vivo administration. Thirty male Wistar rats were divided into five groups (n = 6 each). The control group received DOX via i.p. at a concentration of 4.67 mg/kg BW on days 1 and 4; four treatment groups received PF p.o. at a concentration of 25; 50; 100; 200 mg/kg BW daily, respectively, and additionally DOX i.p. 4.67 mg/kg BW (days 1 and 4) for 7 days. The phagocytic activity was not affected significantly by PF administration compared to the Dox control, but PF administration at a dose of 25 and 50 mg/kg BW has been proven to increase TCD8+ cell proliferation in combination with DOX. The catalase concentration, on the other hand, significantly decreased following PF administration at a dose of 100 mg/kg BW. The results suggest that the polysaccharide-rich fraction of noni juice might induce immunomodulatory effects via TCD8+ activation, have antioxidant activity, and thus might be a potential candidate to be used as an adjuvant to DOX chemotherapy.